During potable water treatment, disinfection primarily results in the removal or inactivation of which target from the water?

Introduction / Context:
Water treatment trains include clarification, filtration, and disinfection. Each step has a distinct purpose. This question focuses on the principal outcome of the disinfection step and differentiates it from aesthetic or hardness control processes.

Given Data / Assumptions:

• Process: disinfection (e.g., chlorine, chloramines, ozone, UV).
• Objective: public health protection.
• Not focused on aesthetic parameters like taste, odor, or hardness.

Concept / Approach:
Disinfection is designed to inactivate pathogenic microorganisms. Turbidity reduction is mainly achieved through coagulation, flocculation, sedimentation, and filtration. Odor control may involve oxidation, air stripping, or activated carbon. Hardness is addressed via lime softening or ion exchange, not by disinfection.

Step-by-Step Solution:

Verification / Alternative check:
Regulatory compliance typically references log removal or inactivation targets for Giardia, viruses, and other pathogens, confirming the primary purpose of disinfection.

Why Other Options Are Wrong:
Turbidity: addressed earlier by clarification and filtration.
Odor: sometimes improved by oxidants, but not the principal metric of disinfection success.
Hardness: controlled by softening processes.

Common Pitfalls:
Assuming any oxidant use equals comprehensive odor removal; overlooking that high turbidity can shield microbes and reduce disinfection efficacy, which is why turbidity control precedes disinfection.

Final Answer:
Bacteria and pathogens